Nature Conservancy scientists are searching for ways to save forests while preserving their unique character.
Photograph: David Levene

In northern Minnesota, there’s a near-mythic expanse of lakes and boreal forests known as the North Woods, packed with spruces, firs, red and bur oaks, and other trees. It’s in danger of vanishing forever.

The North Woods joins the ever-lengthening list of regions threatened by climate change. Temperatures in Minnesota have increased by more than 1.5F since record keeping began, according to a 2013 report by the state’s interagency climate adaptation team. Temperatures have risen even more in the northern portion of the state, and the growth is picking up speed, with more than 80% of the recorded increase happening since 1980. These increases are expected to continue through the next 50 years, joined by more days of extreme heat, heavier precipitation and other changes to the region’s climate. As rainfall and other conditions shift because of climate change, once iconic species like spruce and fir may move northward, either leaving the forests replaced by unproductive grasslands or given over to the hardwoods more common further south. Climate change, the state report says, will “likely exacerbate and intensify the effects of invasive plant species, insect pests, and tree diseases”. In other words, the forest – like others across the northern United States and southern Canada – could disappear. Now the conservationists most driven to save the forest may do so only by changing its nature for good.

Led by Meredith Cornett, the chapter’s science director, the conservancy wants to test “assisted migration”, a lightning-rod conservation practice that broadly means moving species from one region to another either to help that species or the target region adapt to changing conditions.

In actuality, assisted migration is a nuanced concept. The Nature Conservancy study, called the Iron Range Experiment, is a small test meant to compare how specific tree species – and genotypes, or variations – within those species fare under different climate conditions and forestry practices.

Here’s how it will work: Nature Conservancy will plant seeds for 100,000 red oak, bur oak and white pine trees on 2,000 acres of federal, state and local forests in Minnesota’s Iron Range. Seeds from each species will come from two zones: one from within the test range, and another from distant parts of the species’ historic range (mostly from southern Minnesota, and, in some cases, a portion of Michigan where the trees exist).

Researchers from the University of Minnesota Duluth will then manage these test forests in different ways to find out whether varying how the trees are planted and managed affect how each species fares; how different climate conditions affect their viability; and whether seeds originating from other parts of the forest – where different conditions exist – impact how two seemingly identical trees withstand the same conditions.

If the trees moved from distant zones prove to adapt well, this kind of assisted migration could be adopted as a way to maintain the health of forests that might otherwise be decimated by climate change.

Some critics argue that this type of intervention would change the essential character of the forest. Indeed, some of the species being moved are the hardwoods that may one day replace the North Woods’ conifers in any case as a result of climate change.

But Meredith Cornett, the science director of the Nature Conservancy chapter conducting the experiment, compares managing forests to restoring historic buildings. In both cases, she says, sacrifices are controversial – and, perhaps, necessary.

For example, she asks, is it better to restore a historic home to an exact copy of its original construction, or to use modern knowledge and new technologies to protect the structure? When should such a home’s conservationists hew to historic building techniques and finishes, and when should they install new wiring, place well-insulated storm windows and avoid lead-based paint?

“We’re still trying to maintain the character of the home and keep [it] there in the neighborhood, but the world has changed, and we’ve got new tools available to us,” Cornett says.

Assisting or transforming?

The term “assisted migration” was coined after proposals to transplant Torreya Pines from Florida to North Carolina in 2007 sparked heated debate. But Julie Etterson, the University of Minnesota biologist conducting the study with the Nature Conservancy, says the definition of the practice isn’t completely clear. Critics often seem to judge assisted migration projects using a double standard: traditional forestry practices are far more disruptive than the movement of small samples of distant genotypes that are part of the same species, she claims.

“I think that’s a little bit ridiculous given what foresters do, which is wholesale movement of genotypes across the landscape,” Etterson says. “It seems like in the context of the lumber industry that’s fine. In the context of climate change, you’re breaching some sort of conservation barrier that’s inappropriate.”

What’s more, Etterson says, the impact of assisted migration is unclear. In fact, clarifying the process and its effects is a large part of the Iron Range experiment.

“My general feeling is we just don’t know enough about the consequences of genetic mixing to go full force into widespread assisted migration, so I’ve been working with the Nature Conservancy in the design of experiments that we might do,” she says.

Christopher Preston, an environmental ethicist at the University of Montana, says many ecologists would consider Etterson’s form of assisted forestry as different from migration for agriculture or timber because of the intention behind each practice.

“A lot of environmentalists in the environmental ethics community are a little leery of assisted migration because it is [a little] like nature plus the human hand,” Preston explains. “Is it better I have these species here through the help of my hand or to not have this species at all? Is it better to leave some landscapes untouched and let things unfold?”

Many ecologists believe that moving a species, even a tree, from its native ecosystem to put it somewhere else transforms it into something else.

“It’s a little bit like a polar bear in a zoo,” Preston says. “Some people think that’s no longer a polar bear.”

Who benefits from assisted migration?

For Cornett of the Nature Conservancy, Minnesota’s natural and cultural identity is intricately linked, and – she argues – the state needs novel approaches to preserve its North Woods. “It is a wild place and it has tremendous recreational and cultural value, to say nothing of the jobs it supports and so on,” she says.

It’s not hard to see the economic impact of forestry in Minnesota. According to a data sheet provided by the Nature Conservancy, the state’s forests are responsible for 20,000 jobs and more than $2bn in annual wages, as well as $7bn in timber harvest values. The forests are also responsible for hundreds of millions of tourism dollars.

The state’s woodlands also provide considerable quality of life benefits for people in the region. “When it comes to protecting water quality, healthy forests may be as close as we get to a silver bullet,” the Conservancyexplains in its data sheet. “They are nature’s own water purification system, absorbing pollutants and trapping sediment before they damage lakes, rivers and groundwater.”

But while there’s no question that Minnesota’s forests benefit its citizens, Preston says that environmentalism isn’t only about ensuring that nature serves human needs.

“It’s about letting the earth be,” he says. “The ecosystem services language is one you have to use carefully. If it’s about restoring the ecosystem function, then there are arguments to think that that’s probably a good idea. Preserving function with a little bit of help from humans might be something that humanity can do.”

Meddling or stewardship?

While some ecologists believe that humans have meddled enough with the wilderness, others take a more pragmatic perspective. Cornett argues that there is an urgent need to do something to help Minnesota’s forests survive. “We could argue that we should just let nature take its course, but nature has never really faced this situation before,” she says. “We’ve just never seen things changing at this pace.”

Besides, she points out, northern Minnesota’s 6m acres of forests have been managed for more than a century. “My sense is we’re choosing to actively manage a landscape that has already been actively managed,” she says.

Etterson goes even further, saying that, rather than tinkering with nature, the experiment may contribute to re-establishing connections that can no longer happen naturally. “It is a little interventionist, but I don’t think it’s unnatural,” she says.

While management is an ongoing process, it’s becoming more controversial – particularly in light of climate change. In recent weeks, publications ranging from Ensia to the New York Times have covered the topic, which is growing increasingly hot in scholarly circles.

“I was someone who was a real believer of keeping things in their own ranges,” he says. “The quote that hits home for me is that ‘climate change changes everything.’ It’s true. It’s just a game changer.”

Bill Lascher is a freelance journalist based in Portland, Oregon, currently working on a book about World War II-era foreign correspondent Melville Jacoby. His website is www.lascheratlarge.com.